Stress related proteases in Caulobacter crescentus

项目摘要 细菌使用依赖能量的蛋白酶来对压力条件做出反应。这些蛋白水解酶具有双重功能 作用：破坏异常的、潜在有毒的、受损的蛋白质，并通过 调节因素的退化。细胞经常阻止复制以应对压力，但如何调节保护- 细菌的溶解作用导致细胞周期停滞，目前还知之甚少。这份提案阐述了如何 应激相关蛋白利用生化、遗传和蛋白质组学的组合靶向复制因子 方法，特别关注模式细菌Caulbacter的蛋白酶和复制因子 新月星座。目标1和目标2决定了在蛋白毒性应激过程中产生的错误折叠的蛋白质是如何直接刺激的。 使Lon蛋白酶延迟，以破坏复制启动子DNAA，并在应激期间导致生长停滞。AIMS 3 和4重点介绍了ClpXP蛋白酶对钳制加载器亚单位DNAX的部分处理对 DNA损伤过程中的复制应激耐受性。因为这些蛋白水解酶和复制因子 这些结果在所有细菌中都是保守的，将影响我们对复制、蛋白质组学- SIS，和压力耐受性。这些蛋白水解酶在细菌毒力和致病性中的关键作用 在细菌应激反应中对这些蛋白酶的普遍要求，表明它们在细菌应激反应中具有很强的优势。 为开发对人类健康有迫切需要的新的抗生素战略提供了目标。

Project Summary Bacteria use energy dependent proteases to respond to stressful conditions. These proteases serve a dual role: destroying aberrant, potentially toxic, damaged proteins and generating stress responsive signals through degradation of regulatory factors. Cells often arrest replication in response to stress, but how regulated prote- olysis contributes to cell cycle arrest in bacteria is currently poorly understood. This proposal addresses how stress related proteases target replication factors using a combination of biochemical, genetic and proteomic approaches, specifically focusing on proteases and replication factors from the model bacteria Caulobacter crescentus. Aims 1 and 2 determine how misfolded proteins generated during proteotoxic stress directly stimu- late the Lon protease to destroy the replication initiator DnaA and cause growth arrest during stress. Aims 3 and 4 focus on how partial processing of the clamp loader subunit DnaX by the ClpXP protease is critical for replication stress tolerance during DNA damage. Because these proteases and replication factors are highly conserved throughout all bacteria, these results will impact our general understanding of replication, proteoly- sis, and stress tolerance. The critical role of these proteases in bacterial virulence and pathogenicity, together with the universal requirement for these proteases in bacterial stress responses, suggests that they are excel- lent targets for development of new antibiotic strategies that are of immediate human health need.